Technical Session 08: Sensory Session
Jeff E Clawson, Oregon State University, Corvallis, Oregon, USA
Co-author(s): Victor Algazzali, Yanping Qian, Michael Qian, and Thomas Shellhammer, Oregon State University, Corvallis, OR, USA
ABSTRACT: Sour ales from the Northern region of Belgium
are unique in their sensorial aspects, with varying degrees of sourness
and aromatic qualities. These “Flemish” red or brown ales are
traditionally aged in oak barrels for up to 2 years, although some are
aged in stainless steel. Some are blended with younger beer before
packaging. Sour beers brewed in a similar style are being produced by
some U.S. craft brewers. To date, there has been little research
comparing and contrasting the Belgian beers with those produced in the
United States. This research focused on examining this style of beer
from the two respective countries using instrumental and sensory
approaches. Six commercial sour beers from the Flanders region of
Belgium were chosen based on their popularity and availability, while
seven U.S. beers were chosen based on their similarity to the Flemish
sour beer style with regards to aging, color, and sour character.
Instrumental analyses included measures of acidity (pH, TA, and organic
acid profiles), volatile aromas (ethyl and lactate esters), and markers
of Brettanomyces activity (4-ethylphenol and 4-ethylguiacol).
Descriptive sensory analysis was performed using a panel of 13 trained
beer tasters and a ballot of 22 attributes. The U.S. beers were
significantly higher and more variable in OG, ABV, and acidity than
their Belgian counterparts but were similar in visual appearance and
color. The U.S. beers were perceived as being more bitter, salty, sour,
and astringent, with greater Brettanomyces character than the
Belgian beers, while the Belgian beers tended to be sweeter and
possessed greater coca/coffee notes. There was less differentiation
between the two countries for descriptive terms such as dark fruit,
cherry, fruity, caramel, tobacco/black tea, and sweaty/cheesey.
Instrumental results of esters and Brettanomyces markers mirrored
these similarities. These results reveal that sour beers originating
from the United States and Belgium have many similarities, while at the
same time expressing their own uniqueness.
Jeff Clawson
received both his M.S. and B.S. degrees from Oregon State University in
Corvallis, OR. In 1993 he began employment with the Food Science and
Technology Department at OSU as a faculty research assistant working
with Mina McDaniel. He conducted both descriptive and commercial sensory
panels involving beer and food products. Since 2001 he has been
professional faculty, managing both the food processing plant and
research brewery, supporting the research program of Thomas Shellhammer.
He has been an active member at the local level of the Institute of
Food Technologists, ASBC, and MBAA.
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